Feed adjusting mechanisms for sewing machines



June 4, 1957 F. PARRY 2,794,408

FEED ADJUSTING MECHANISMS FOR SEWING MACHINES Filed April 26, 195s 4 Sheets-Sheet 1 INVENTOR Frank Parry WITNESS 7 fl/M BY 6 ATTORNEY F. PARRY 2,794,408

FEED ADJUSTING MECHANISMS FOR SEWING MACHINES June 4, 1957 4 Sheets-Sheet 2 Filed April 26, 1955 u 3 H n i 3, w

INVENTOR Frank Parry BY -LM/ ATTORNEY June 4, '1957 2,794,408

FEED ADJUSTING MECHANISMS FOR SEWING MACHINES F. PARRY 4 Shets-Sheet :5

Filed April 26, 1955 Fig.4

INVENTOR Frank Parry BY Q4,

ATTORNEY WITNESS MMLMWJM F. PARRY 2,794,408

FEED ADJUSTING MECHANISMS FOR SEWING MACHINES June 4, 1957 4 Sheets-Sheet 4 Filed April 26, 1955 w Y Ra E M W Ek w w n mm A F H W Y 8 mm FEED ADJUSTING MECHANISMS FOR SEWING MACHINES Frank Parry, Trumbull, Conn, assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application April 26, 1955, Serial No. 503,883

8 Claims. (Cl. 112210) This invention relates to sewing machines and, more particularly, to a mechanism for adjusting the eccentricity of an eccentric actuator for one or more of the instrumentalities of a sewing machine.

it is an object of this invention to provide an eccen-. tric control mechanism which operates directly upon the eccentric to vary not only the degree of eccentricity but to change its eccentricity by 180.

Another object of this invention is to provide an eccentric control mechanism of the above character which operates smoothly and with a minimum of frictional resistance.

Still another object of this invention is to provide an eccentric reversing mechanism which may be actuated quickly and substantially efiortlessly during operation of the sewing machine.

With the above and additional objects and advantages in view, as will hereinafter appear, this invention comprises the devices, combinations, and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

7 Fig. 1 represents a front elevational view of a portion of a sewing machine having the present invention applied thereto with portions of the machine frame and of the mechanisms broken away and illustrated in vertical cross section,

Fig. 2 is a bottom view of the sewing machine illustrated in Fig. l,

. Fig. 3 represents an enlarged top plan view of a fragment of the eccentric reversing mechanism,

Fig. 4 is a cross sectional view taken substantially along line 44 of Fig. l,

Fig. 5 represents a front elevational view of a fragment of the sewing machine illustrated in Fig. 1 having a modified form of eccentric reversing mechanism applied thereto, and

Fig. 6 is a cross sectional view taken substantially along line 66 of Fig. 5.

In the drawings, the present invention is illustrated in a preferred embodiment as applied to the work feed advance driving eccentric, the work feeding mechanism being properly classifiable with the needle and loop-taker as stitch forming instrumentalities, since the nature of the advance of the work fabric determines the spacing and progression of thread convolutions between successive stitches.

In the accompanying drawings, a sewing machine is illustrated of the type adapted to be fitted with both an upper and an under work-feeding mechanism, that is, a mechanism in which the fabrics are transported by opposed feeding members operating in concert one beneath the fabric and one above the fabric. This sewing machine, as well as the construction of the Work feeding mechanism, is illustrated and fully described in my copending U. S. patent application Serial No. 432,382, filed May 26, 1954, to which reference may be had for a detailed description. For an understanding of the present invention, however, the following general descripted States Patent tion of the sewing machine and of the work feeding instrumentalities will be suflicient.

The sewing machine frame is of conventional form comprising a bed 11 and a bracket-arm 12. Journaled in the bracket-arm is a main shaft 13 fitted with a balance wheel pulley 14 by which the sewing machine may "be driven in the usual fashion from a power transmitter. Iournaled lengthwise in the bed is a bed shaft 15 adapted to be rotated in timed relation with the main shaft 13 by means of a belt 16. As shown in Fig. 2, spur gears 1717 fast on the bed shaft serve to drive vertical axis rotary hook shafts 1818 journaled in individual hook saddles 1919 beneath the bed.

Rotary hooks carried one by each of the hook shafts 13-48 cooperate in the formation of stitches with a pair of endwise reciprocatory needles fastened in a needlebar jourualed in the bracket-arm and actuated from the main shaft 13. This mechanism being conventional and not directly concerned with the present invention has been omitted from the drawings.

In Fig. 2, portions of the under feed mechanism are illustrated. The under feed is of the four-motion drop feed variety in that it comprises a feed bar 21 which may be provided with a roughened or serrated work engaging dog (not shown) together with mechanism for lifting and advancing and then lowering and retracting the feed bar. The feed bar is bifurcated, as at 22, and embraces a feed lift eccentric 23 fast on the bed shaft 15 by which the lifting and lowering motions of the feed bar are derived. For the feed advance and return motions, the feed bar is pivotally secured to a rock frame 24 carried by a feed advance rock shaft 25 journaled beneath the bed. The rock shaft 25 is actuated by means of a pitman 26 embracing a feed advance eccentric 27 carried on the bed shaft 15.

The upper work feeding mechanism may be substantially the same as that disclosed in my previously mentioned prior application Serial No. 432,382. This mechanism is not disclosed in the accompanying drawings save for the top feed advance rock shaft 28 which is journaled in bearings such as 29 in the bracket arm. The top feed advance rock shaft 28 functions in a comparable capacity with respect to the top feed mechanism as does the feed advance rock shaft 25 with respect to the under feed mechanism, i. e., to impart feed advance and return motions to the feeding instrumentalities. In order that both of the feeding instrumentalities may be actuated in synchronism, the top feed advance rock shaft 28 is driven from the feed advance rock shaft 25 in the bed by means of a rock arm 30 fast on rock shaft 25, a link 31 and a rock arm 32 fast on the top feed advance rock arm 23.

The eccentric member 27 has formed integrally therewith a transverse guide plate 40 of which the side edges 4141 are beveled as is best illustrated in Fig. 3. The eccentric member is formed with a clearance bore 42 so that the eccentric may partake of movement radially of the bed shaft 15 on which it is carried. Secured on the bed shaft 15, as by set screw 43, is an eccentric body member 44 formed with a transverse guideway 45 having undercut side edges slidably to accommodate the guide plate 40 of the eccentric member. Supported on the eccentric body member 44 is a bell crank 46 fixed by a set screw 47 to a fulcrum pin 48 disposed transversely of the bed shaft 15. The extremity of one arm 49 of the bell crank 46 is fitted with a cyliudrically tipped finger 50. This arm of the bell crank is disposed substantially parallel to the axis of the bed shaft and the cylindrical extremity of the finger 50 is disposed to extend into a slot 51 formed in the transverse guide plate 40 of the eccentric member 27. The bell crank 46 is formed with an arched portion or yoke defining spaced depending arms 5252 arranged to straddle the eccentric body member, the arms 52-52 being fitted with screws 53-53 of which the enlarged heads are embraced by slotted fingers 54-54 which are secured as by screws 55 to extend from a thrust collar 56 arranged for sliding movements axially 'along the bed pair of spaced lugs 5959 which slidingly embrace a.

guide pin 60 fixed in the eccentric body member 44 and disposed to extend parallel to the bed shaft 15 so as to lock the thrust collar for rotation with thebed shaft without interfering with axial sliding movements of the collar.

In the construction illustrated in Figs. 1 to 4, the thrust collar 56 is formed with spaced radial flanges 61 and 62 defining therebetween an annular groove 63 bounded. by opposed sidewalls 64 and 65 defined by the flanges 61 and 62 respectively. Extending into the annular groove 63 is a roller 66 carried by the depending arm 67 of a bell crank 68 fulcrumed, as at 69, in a block 70 secured beneath the bed 11 of the machine frame. The bell crank 68 is formed with a sustantially horizontal arm 71 offset as illustrated in Fig. 2 and pivotally secured by a pin 72 to the depending extremity of a substantially vertical rod 73 slidably supported in a bracket 74 secured to the machine bed 11, as by the fastening screws 75. The bracket 74 is slotted, as at 76, to accommodate a flanged stud 77 extending from the slide rod 73. The stud 77 serves to prevent the slide rod from turning and also is tapped to receive a pivot screw 78 operatively to connect the slide rod with an operator influenced lever 79 which is fulcrumed, as at 80, to a block 81 secured on the outside of the machine standard 12. The lever 79 preferably extends from the fulcrum 80 toward the stitching point, that is to the left as viewed in Fig. l, and is provided at itsfree extremity with a flattened extension. 82 which the operator may engage conveniently with her arm'or I Threaded into the side of the slide rod 73 is an. abut ment in the form of a. pin 90 extending through a. slot 91 formed in the bracket 74. Movement of the slide rod 73.

is limited by means of a pair of' stop nuts 92 and 93 carried on threaded sections 94 and 95, respectively, of a shaft 96 journaled in lugs 97 and 98 extending from the bracket member 74. The sections 94 and 95 are formed each with a thread of the opposite hand, and the nuts 92 and 93 are constrained by means of a backing'plate 99 against turning movement with the shaft 96. The shaft 96, therefore, acts upon the stop nuts 92 and 93 after the fashion of a turnbuckle to draw together or separate the nuts 92 and 93. The shaft 96 may be turned in either direction by a knurled thumb wheel .100 fixed thereto and disposed as shown in Fig. 4 to extend through a clearance slot 101 in the machine standard 12 so as to be accessible conveniently to the machine operator. A clamp screw 102 extends through a clearance opening 103 in the standard and is threaded into the bracket 74 to provide alock for securing the shaft 96, and hence the stop nuts 92 and 93, in selective position relatives one to the other.

A pin 104, extending from the lower extremity of the slide rod 73, is engaged by the lower end of a coil spring 105 disposed substantially vertically in the standard 12' and being anchored at its upper end to a pin 106 fixed in the machine frame. The coil spring 105 serves to bias the entire eccentric controlling mechanism into the position as shown in Fig. l in which the eccentric member is both the forward and reverse direction of feed at any particular position of the lever 79.

The position of the lever 79 may, therefore, be shifted rapidly by depression of the flattened extension 82 so as to act by way of the slide rod 73, bell crank 68, thrust collar 56 and bell crank 46 to effect a complete reversal of the position of the eccentric member 27 with respect to the shaft, i. e., at 180 shift of the eccentricity, thus instantaneously reversing the direction of the feed of the work. The lever 79 may also be shifted by means of the.

knurled hand wheel 100 afiording a micrometer adjustment of the stitch length. In the construction illustrated in Figs. 1 through 4, both stop nuts 92 and 93 are adjusted simultaneously toward or away from each other so that the maximum stitch length in the forward direction, as determined by the upper stop nut 92, will always equal the maximum. stitch length in the reverse 1 direction, as determined by the lower stop nut 93.

Figs. 5 and 6 illustrate a modified form of the feed] advance eccentric controlling mechanism of this inven-.

tion in which the maximum eccentricity in the forward and in the reverse position, of the parts may be varied ;.independently as, for instance, if an appreciably longer or shorter stitch were desired during reverse. stitching than during normal stitching in the forward direction.

In the modified form of Figs. 5 and 6, the same eccentric member 27 and eccentric engaging bell crank 46 is utilized, this bell crank 46 being fulcrumed on an eccena single flange 111 providing an end face which is preferably formed with a raised annular rib 112 against which bears the roller 66 of the bell crank 68. As in the previously described arrangement, the bell crank 63 is ful-.

crumed at 69 to a block 70 carried by the machine bed -11 and is formed with a short depending arm 67 carrying particularly, the annular rib 112 thereof into engagement the roller 66 and with an elongated horizontal arm 71. A coil spring 113 arranged in compression in the counterbore 58 between the eccentric body portion 44 and the thrust collar serves to urge the thrust collar and,

with the roller 66. Pivotally secured by means of a pin 114 to the extremity of the horizontal arm 71 is a link- 115 extending within the standard and at its upper extremity embracing a pin 116 extending through a substantially vertical slot 117 formed in the standard. The

pin 116 is embraced at the outside of the standard in a' 'end in the bed 11 and at the opposite end in a bracket 126 secured to the standard 12. The stop nuts 123 and 124 are disposed one at each side of the boss 118, which boss constitutes an abutment member and cooperates with the stop nuts to limit movement of the hand lever 119T A coil spring 127 arranged between the stop nuts 123 and 124 serves frictionally to prevent accidental turning thereof.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine having a frame, a shaft journaled in said frame, an eccentric carried for rotation on said shaft, and means slidably supporting said eccentric for bodily movement transversely of and relative to the axis of said shaft, an eccentric adjusting mechanism comprising, a first bell crank pivoted on said frame, a second operative engagement with said eccentric, a member operatively interconnecting said bell cranks, said member being constrained for rotation with said shaft but slidable axially thereof, and operator influenced means carried by said frame for turning said first bell crank.

2. In a sewing machine having a frame, a shaft journaled in said frame, an eccentric carried for rotation on said shaft, and means slidably supporting said eccentric for bodily movement transversely of and relative to the axis of said shaft, an eccentric adjusting mechanism comprising, a first bell crank pivoted on said frame, operator influenced means carried by said frame for turning said first bell crank, a roller carried by said first bell crank, an endwise shiftable member constrained for rotation with said shaft but slidable axially thereof, said member being formed with an annular face disposed for engagement by said roller, and a second bell crank carried on a pivotal axis disposed transversely on said shaft, said second bell crank being operatively connected at one side of said pivotal axis with said endwise shiftable member and at the other side with said eccentric.

3. In a sewing machine having a frame, an actuating shaft journaled in said frame, and stitch forming instrumentalities adapted to be actuated by said shaft, an eccentric adjusting mechanism comprising, an eccentric body fast on said shaft, said eccentric body being formed with a transverse guideway having undercut side edges, an eccentric, a transverse guide plate having beveled side edges carried by said eccentric and slidably arranged in said guideway, a bell crank pivotally secured to said eccentric body on an axis which is perpendicular to said transverse guideway, one arm of said bell crank being operatively associated with the transverse guide plate of said eccentric, a member slidable axially on said shaft and operatively connected with the other arm of said bell crank, interengaging means on said member and on said eccentric body constraining said member for rotation with said eccentric body, a control lever carried by said frame and disposed in operative engagement with said slidable member to dictate the position of said member axially of said shaft, and operator influenced means carried by said frame for turning said control lever.

4. An eccentric adjusting mechanism as set forth in claim 3 in which said slidable member is formed with an annular groove defined between axially spaced radially extending side walls, and a roller carried by said control lever and disposed to track said annular groove.

5. An eccentric adjusting mechanism as set forth in claim 3 in which said slidable member is provided with a shoulder formed with a radially extending face, a roller carried by said control lever and disposed to abut said radially extending face, and spring means arranged between said slidable member and said eccentric body acting to bias said slidable member into engagement with said roller.

6. In a sewing machine having a frame, a shaft journaled in said frame, an eccentric carried for rotation on said shaft, and means slidably supporting said eccentric for bodily movement transversely from one side to the other of the axis of said shaft, an eccentric reversing mechanism comprising, a first bell crank pivoted on said frame, a second bell crank carried on a pivotal axis disposed transversely on said shaft, said second bell crank being arranged in operative engagement with said eccentric, a member operatively interconnecting said bell cranks, said member being constrained for rotation with said shaft but slidable axially thereof, mechanism for turning said second bell crank including a lever constituting a handle carried by said frame, operative connections between said lever and said second bell crank, and means limiting the maximum eccentricity of said eccentric, said means including an abutment carried by the turning mechanism for said second bell crank, a pair of stop members extending into the path of said abutment, and means supporting said stop members each on an opposite side of said abutment and for selective adjustment toward and away from each other.

7. In a sewing machine having a frame, a shaft journaled in said frame, an eccentric carried for rotation on said shaft, and means slidably supporting said eccentric for bodily movement transversely from one side to the other of the axis of said shaft, an eccentric reversing mechanism comprising, a first bell crank pivoted on said frame, a second bell crank carried in a pivotal axis disposed transversely on said shaft, said second bell crank being arranged in operative engagement with said eccentric, a member operatively interconnecting said bell cranks, said member being constrained for rotation with said shaft but slidable axially thereof, mechanism for turning said second bell crank including a lever constituting a handle carried by said frame, a rod slidably supported for endwise movement in said frame, said rod being operatively connected between said lever and said second bell crank, and means limiting the maximum eccentricity of said eccentric including an abutment member extending radially from said slide rod, a threaded stud carried by said frame substantially parallel to said slide rod and a pair of stop nuts on said stud, said stop nuts being disposed in the path of said abutment member each on an opposite side thereof.

8. In a. sewing machine having a frame, a shaft journaled in said frame, an eccentric carried for rotation on said shaft, and means slidably supporting said eccentric for bodily movement transversely from one side to the other of the axis of said shaft, an eccentric reversing mechanism comprising, a first bell crank pivoted on said frame, a second bell crank carried on a pivotal axis disposed transversely on said shaft, said second bell crank being arranged in operative engagement with said eccentric, a member operatively interconnecting said bell cranks, said member being constrained for rotation with said shaft but slidable axially thereof, mechanism for turning said second bell crank including a lever constituting a handle carried by said frame, operative connections between said lever and said second bell crank, and means limiting the maximum eccentricity of said eccentric, said means including an abutment carried by the lever, a threaded stud carried by said frame, a pair of stop nuts on said stud, said stop nuts being disposed in the path of said abutment each on an opposite side thereof.

Best Nov. 4, 1947 Biesemeyer et al May 25, 1954 

